item components + inventory sync by Sweattypalms · Pull Request #330 · ferrumc-rs/ferrumc

Sweattypalms · 2026-01-25T12:10:08Z

item components + inventory sync + inventory saving into database with components is fixed now.

idk if float and list types are added or not, change if not.

Implements the complete Minecraft 1.21.x item component system with NetEncode/NetDecode support for server-client item data serialization. Key changes: - Add all component types (IDs 0-95): custom data, enchantments, food, consumables, tools, weapons, potions, fireworks, entity variants, etc. - Add helper enums: Rarity, DyeColor, EquippableSlot, ConsumableAnimation, AttributeModifierOperation, FireworkExplosionShape, and entity variants - Add helper structs: PotionEffect, FireworkExplosion, SoundEvent, BlockPredicate, TrimMaterial, TrimPattern, Instrument, JukeboxSong, etc. - Implement ID-or-inline patterns for registry references - Fix IDSet codec with proper encode/decode implementations - Add RawNbt wrapper for arbitrary NBT component data Note: 4 components with NBT<TextComponent> fields use todo!() for decode as TextComponent doesn't yet implement FromNbt.

added a few new components

…ation

- Add Component factory methods for cleaner item creation (custom_name, lore, max_stack_size, etc.) - Add ItemBuilder fluent API following TextComponentBuilder pattern - Create storage layer with StorageComponent, StorageInventorySlot for bitcode serialization - Add StorageInventory, StorageEnderChest, StorageOfflinePlayerData with From/TryFrom conversions - Re-enable player data persistence in world_sync, connection_killer - Load saved player data (position, gamemode, abilities) on login

- Add streaming NBT reader for network format (read_nbt_bytes) - Implement nameless NBT parsing for TextComponent decoding - Add roundtrip tests for CustomName and multi-component slots - Fix NbtTape usage that expected named NBT format Note: Still debugging client-to-server NBT decode issue

…ocol The Minecraft protocol uses asymmetric encoding for slot component data: - Server → Client: ComponentID + Data (no length prefix) - Client → Server: ComponentID + Length + Data (with length prefix) Changes: - Component::decode now reads length prefix before component data - Parse component data from bounded buffer for safety - TextComponent parsing updated to not double-read length prefix - Lore elements use streaming NBT reader (no per-element length) - Roundtrip tests marked ignored (asymmetric format by design) This fixes the "Invalid NBT tag type: 15" error when client sends slot data back to server (e.g., creative mode item duplication).

- Initial inventory sync: sends full inventory via SetContainerContent on join - Equipment broadcast: other players see armor/held items via SetEquipment packet - Join equipment exchange: new players see existing players' gear and vice versa - Plugin hooks: InventorySynced, EquipmentChanged, HeldItemChanged messages Also fixed timing bug in give_test_item.rs and join_equipment_exchange by using Added<PlayerIdentity> instead of PlayerJoined message, ensuring entities are queryable after Bevy commands are applied.

Kept both inventory sync components and master's emit_player_joined pattern.

The manual NetEncode impl was only writing payload data without the packet ID, causing clients to misparse the packet as bundle_delimiter (ID 0) and crash. Solution: Move the equipment list encoding logic to a wrapper type (EquipmentList) and let the derive macro handle proper packet framing.

- Remove debug logging from slot.rs that read entire streams into buffers - Replace 18 unsafe transmutes with safe enum conversion functions - Remove dead component_id_name() function - Add helper methods to EquipmentState (non_empty_slots, is_empty) - Gate give_test_item system behind #[cfg(debug_assertions)] - Add clippy expect for complex query types

ReCore-sys · 2026-01-25T13:01:59Z

src/bin/src/systems/listeners/give_test_item.rs

+
+/// Gives new players a test item with components.
+/// Uses `Added<PlayerIdentity>` to detect new players after commands are applied.
+pub fn handle(


Could this be a command instead?

ReCore-sys · 2026-01-25T13:08:16Z

src/lib/components/src/player/offline_player_data.rs

If there is now a conversion between in-memory and disk format, can we use the unserializable Position here?

- Add limits.rs with MAX_NBT_SIZE (2MB) and MAX_NBT_DEPTH (512) - Validate NBT lengths are non-negative before allocation - Track and enforce depth limits on compound/list recursion - Add size limit checks before all NBT allocations - Fix negative VarInt cast in component decoding - Add error logging for storage conversion failures - Replace all todo!() panics with graceful error handling - Add AsyncNotSupported error variants for unimplemented async paths Prevents memory exhaustion attacks from malicious NBT data and eliminates potential panics in production from unimplemented code paths.

@ReCore-sys

- Convert give_test_item auto-join system to /givetest command - Use Position type in OfflinePlayerData instead of tuple - Keep (f64, f64, f64) in StorageOfflinePlayerData for serialization Addresses feedback from @ReCore-sys on PR #330.

ReCore-sys · 2026-01-28T07:35:03Z

src/bin/src/packet_handlers/play_packets/update_survival_mode_slot.rs

-                                components_to_remove: None,
-                                components_to_add_count: None,
-                                components_to_remove_count: None,
+                                components_to_add: Vec::new(),


Shouldn't these have the count or am I missing something?

Counts were intentionally removed. They're not derived from Vec::len() during encoding. Explicit count fields were redundant and a source of potential count/data mismatch bugs.

ReCore-sys · 2026-01-28T07:37:08Z

src/bin/src/systems/inventory_sync.rs

+pub fn initial_inventory_sync(
+    mut commands: Commands,
+    state: Res<GlobalStateResource>,
+    query: Query<(Entity, &Inventory, &StreamWriter), With<NeedsInventorySync>>,


The marker component is not removed/added in the same order every tick, you should probably use a normal component with a flag in it

Replaced NeedsInventorySync marker with Bevy's Added<Inventory> filter and added an explicit .after(emit_player_joined) ordering constraint. Eliminates the marker entirely and guarantees the system runs after ApplyDeferred flushes the entity.

ReCore-sys · 2026-01-28T07:45:17Z

src/lib/adapters/nbt/src/de/streaming.rs

+    /// Total bytes read so far
+    bytes_read: usize,
+    /// Current nesting depth (compound/list)
+    depth: usize,


If the depth is capped at 512 this should be a u16

usize is idiomatic for sizes/indices and avoids casts at every usage site. It's a stack-local value, the 6 bytes saved don't matter.

ReCore-sys · 2026-01-28T07:46:47Z

src/lib/adapters/nbt/src/de/streaming.rs

+/// Tracks state during NBT reading for security validation.
+struct NbtReadState {
+    /// Total bytes read so far
+    bytes_read: usize,


If size read is 2MB this should be a u32

usize matches what Vec::len() and slice methods return. Using u32 would just add as usize casts everywhere.

ReCore-sys · 2026-01-28T07:49:49Z

src/lib/adapters/nbt/src/de/streaming.rs

+
+/// Reads the payload for an NBT tag (after the tag type byte).
+///
+/// This function is recursive for compound and list tags.


Are stack overflows handled? The recursion depth is technically capped at 512, but is this deep enough to cause a stack overflow?

512 is the same limit Minecraft's own NBT parser uses. Stack usage per frame is a few small fixed buffers and pointer-sized locals, not a concern.

ReCore-sys · 2026-01-28T08:01:51Z

src/lib/components/src/player/gameplay_state/ender_chest.rs

+
+/// Storage-friendly ender chest for bitcode persistence.
+#[derive(Clone, Debug, Encode, Decode)]
+pub struct StorageEnderChest(pub StorageInventory);


Same as other storage formats, why?

see my reply on storage.rs

ReCore-sys · 2026-01-28T08:02:39Z

src/lib/inventories/src/components.rs

+//! Item component types for the Minecraft protocol.
+//!
+//! This module implements all item components as defined in the
+//! [Minecraft protocol documentation](https://minecraft.wiki/w/Java_Edition_protocol/Slot_data).


This URL should target 1.21.8, not the latest

ReCore-sys · 2026-01-28T08:03:41Z

src/lib/inventories/src/slot.rs


-#[derive(Debug, Clone, Hash, Default, PartialEq, Decode, Encode)]
+/// Represents an inventory slot with item data and components.
+/// See: https://minecraft.wiki/w/Java_Edition_protocol/Slot_data


This url should point at 1.21.8, not latest

Slot_data page isn't referenced by versions unlike the protocol page iirc

ReCore-sys · 2026-01-28T08:06:00Z

src/lib/net/src/packets/outgoing/set_equipment.rs

@@ -0,0 +1,78 @@
+//! SetEquipment packet for broadcasting player equipment to other players.
+//! Protocol: https://minecraft.wiki/w/Protocol#Set_Equipment


This URL doesn't point to anything helpful, and for the latest version

ReCore-sys · 2026-01-28T08:06:46Z

src/lib/net/src/packets/outgoing/set_equipment.rs

+        _writer: &mut W,
+        _opts: &NetEncodeOpts,
+    ) -> Result<(), NetEncodeError> {
+        unimplemented!("Async encoding not needed for server-to-client packets")


Why do you not have it implemented here but implemented in other files?

ReCore-sys and others added 15 commits January 19, 2026 19:05

FML

591e75e

added a few new components

b358f0f

idk if float and list types are added or not, change if not.

Merge pull request #321 from HajimeOnodera56/patch-1

a8643cb

added a few new components

Merge origin/feature/item-components, keep protocol-correct implement…

9e13fba

…ation

test with temp items

43348e0

add item and update components given

add79b8

merge: resolve conflicts with master

1b65451

Kept both inventory sync components and master's emit_player_joined pattern.

cargo fmt

a143680

ReCore-sys suggested changes Jan 25, 2026

View reviewed changes

Sweattypalms added 2 commits January 25, 2026 22:18

refactor: address PR review feedback

0b1bb1e

- Convert give_test_item auto-join system to /givetest command - Use Position type in OfflinePlayerData instead of tuple - Keep (f64, f64, f64) in StorageOfflinePlayerData for serialization Addresses feedback from @ReCore-sys on PR #330.

ReCore-sys suggested changes Jan 28, 2026

View reviewed changes

		@@ -0,0 +1,78 @@
		//! SetEquipment packet for broadcasting player equipment to other players.
		//! Protocol: https://minecraft.wiki/w/Protocol#Set_Equipment

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Sweattypalms commented Jan 25, 2026 •

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